Antiperspirants are popular personal care products used to prevent or eliminate perspiration and body odor caused by perspiration. Antiperspirant products, including for example sticks, emulsions, aerosol sprays, and roll-on antiperspirants are desired by a large majority of the population because of the presence of active antiperspirant compounds that minimize or prevent the secretion of perspiration by blocking or plugging ducts of sweat-secreting glands, such as those located at the underarms. Antiperspirants typically include an active antiperspirant compound in a carrier that permits the antiperspirant product to be applied to the skin by swiping or rubbing the stick across the skin, typically of the underarm. Upon application of the antiperspirant product, the carrier coats the skin or evaporates, releasing the active antiperspirant compound from the antiperspirant product upon exposure to moisture to form plugs in the sweat ducts.
Active antiperspirant compounds reduce underarm wetness and odor by migrating into openings of the sweat gland ducts and reacting with proteins therein to form antiperspirant plugs, which mechanically prevent sweat from escaping the ducts. Two types of sweat glands are present in the underarm region. The first type of sweat gland, the apocrine sweat gland, terminates and secretes at the top of hair follicles. As such, active antiperspirant compounds should migrate into the hair follicle to access the apocrine sweat gland duct and block secretion. The second type of sweat gland, the eccrine sweat gland, opens directly onto the skin. Eccrine sweat is responsible for the largest volume of sweat that causes underarm wetness. As with apocrine sweat glands, active antiperspirant compounds migrate into the eccrine sweat gland openings and form plugs, which reduce underarm wetness.
Some antiperspirant compositions known in the art of the stick type include one or more structurant compounds, which are included to provide good “glide” qualities (i.e., ease of application when the stick is moved across the underarm region) and to minimize residue deposits on the skin. Exemplary structurant compounds currently known in the art include intermediate molecular weight polyethylenes, such as polyethylenes having an average molecular weight between about 360 Daltons and 460 Daltons.
The manufacture of such polyethylene structurants, however, requires the use processing conditions that are undesirable. For example, where the above-noted intermediate molecular weight polyethylenes are employed in an antiperspirant composition, it is necessary to melt the polyethylenes before they can be combined with the active antiperspirant compound. Such melting requires the use of undesirably high processing temperatures in the manufacturing process, such as at least about 85° C., which corresponds with the approximate melting point of these intermediate molecular weight polyethylene compounds.
As is well known in the art, high processing temperatures not only consume high operation energy, but it also increases the risk of corrosion on the manufacturing equipment. For example, certain active antiperspirant compositions increase in acidity with increasing temperature, thereby causing an increased risk of corrosion to the manufacturing equipment. Furthermore, the use of such high operating temperature increases both the complexity and cost of manufacturing the antiperspirant composition by requiring additional heating elements to achieve the higher temperature and additional safety precautions for the personnel operating the equipment.
Accordingly, it is desirable to provide antiperspirant compositions that exhibit the same or similar glide and residue deposition qualities as antiperspirant compositions that intermediate molecular weight polyethylenes, but that do not require excessively high processing temperatures for their manufacture. Further, it is desirable to provide methods for preparing these antiperspirant compositions. Still further, other desirable features and characteristics of the present disclosure will become apparent from the subsequent detailed description the appended claims, taken in conjunction with the accompanying drawings and background.